Apparatus and method for filling containers with predetermined quantities of gas



VJuly 21, 1953 P. F. DRosTE |=:r Al.

WITH PREDETERMINED QUANTITIES 0F GAS Filed lay 14, 1951 APPARATUS AND METHOD FOR FILLING CONTAINERS 2 Sheets-Sheet l IN VEN TORS July 21, 1953 P. F. DRosTE Erm. 2,645,907

APPARATUS AND METHOD Foa FILLING CONTAINERS WITH PREDETERMINED QUANTITIES 0F GAS 2 Sheets-Sheet 2 Filed Hay 14, 1951 mw n, m .a r www, wf. #4% m H Patented July 21, 1953 UNITED. STATES PATENTKOFFICE.

APPARATUS AND METHOD FORKFILLING CONTAINERS WITH PREDETERMINED QUANTITIES OF GAS Paul F. Droste, Glen Ellyn, Ill., and Howard J. Hill, deceased, late of Millvalc, Pa., by Charlotte R. Hill, administratrix, Millvale, Pa., assignnrs to National Cylinder Gas Company, Chicago, Ill., a corporation of Delaware Application May 14, 1951, Serial No. 226,176

14 claims. (cl. faz- 1) This invention relates to improvements in systems for filling cylinders or like containers withpredetermined quantities of a gas under pressure, and it includes apparatus and methods for accomplishing this in a simple and economical manner that does not require the use of gauges, scales or other measuring devices in connection with the filling operation. More specifically, the invention is concerned With'iilling cylinders 0r other containers with carbon dioxide gas, and this iS acomplished in accordance with the invention by introducing a fixed and automatically controlled amount of liquefied carbon dioxide into the container, whereupon absorption of heat from the atmosphere serves to vaporize the liquid to provide the desired amount of carbon dioxide gas in the container under the required Working pressure.

It is common knowledge that the pressure exerted by a given quantity of gas conned in a container varies directly with the temperature of the gas. Accordingly, it has been yfound necessary in connection with containers for gases to take steps to limit the quantity of gas in a given container in order that unsafe pressures will not be developed under the temperature conditions that may be encountered in the handling and use of the gas so confined. To this end, the Bureau of Explosives of the Interstate Commerce Commission has provided specications for various gas containers, including the usual gas cylinders, and has specied the iilling densities for these in terms of the weight of the maximum quantities of various gases that may be safely stored in them without danger of cylinder or container failure with increase in temperature. For example, a common type of standard ity pound cylinder for carbon dioxide gas may saiely containy up to a maximum of 51 pounds of the gas, but no more. Because carbon dioxide has the characteristic of existing in liquid state in equilibrium v"with its gaseous state under relatively low pressures, it is possible by simple calculation to determine the safe iilling density for a standard carbon dioxide cylinder in terms of a depth of liquefied gas in the cylinder at a given temperature of the liquid.

Two general methods havev been used heretofore for introducing carbon dioxide into containers for its storage and subsequent use. One of these, usually designated as the high pressure system, comprises pumping the gas at normal temperatures and under the required high pressure into the cylinder or container until there is compressedy therein the required or permissible weight of the carbon dioxide gas in ,compressed form. The ether method, usually 2 called the low pressure system, comprises refrigerating both the bulk supply of gas and the container into which it is to be transferred to a temperature at which the gas may be handled in liquid state at relatively low pressure. Thereupon, the required amount of liquid is transferred by pumping or gravity into the container to be filled. The iirst method, or high pressure system, requires the use of a gas pump or compressor capable of attaining the required degree of compression, and involves other equipment for withstanding high pressure, including special pipes and fittings. The low pressure system requires refrigeration to maintain the temperature ofthe containers sufficiently low to maintain lthe low pressure under which the liquelied gas may be safely handled and stored. With both methods, it is necessary to measure the quantity of gas transferred, usually by weighing the individual receivingcontainers (or the bulk source of supply), both' before and after the iilling operation, to insure that the proper amount of gas has been transferred in whatever state it is supplied.A It

will be readily appreciated that measuring theV f) gas or weighing the containers requires special equipment and is a time-consuming operation, and therefore costly, particularly when a number of -relatively small cylinders or containers are being lled.

` Neither of the systems just discussed lends itself well to the filling of containers which are permanently installed, for example, in establishments removed from facilities for producing. the gas. Low pressure permanently installed bulk containers have beenv developed and are used which may be iilled by the 10W pressure method from a refrigerated mobile supply tank. But such containers must be equipped with refrigeration means as above mentioned, and it has been found necessary in nearly all cases to provide for heating the containers after the iilling operation has f been completed, in order to bring the pressure of carbon dioxide gas above the liquid up to the desired pressure for its use in gaseous form. The use of the high pressure method for filling permanently installed containers would involve the transportation of both a bulk supply of gas and a high pressure gas pump or compressor to the location of the containers, and this method has, so far as Wer are aware, never been found to be practical.

To overcome the disadvantages inherent in these prior methods, we have devised the present apparatus and method which is more flexible, economical and simple than other systems for the provision of a permanently installed storage supquantity of gaseous carbon dioxide`in the container. provide a simple and inexpensive method for filling unrefrigerated high pressure cylinders or containers with carbon dioxide gas in controlled amounts. A further object is to provide an apparatus and method for efficiently and economically filling permanently installed containers for Another object of our invention is to' carbon dioxide gas from a mobile bulk supply of liquefied carbon dioxide. Still another object is to provide a means for rapidly and sequentially filling a plurality of containers for carbon dioxide under pressure with predetermined` amounts of the gas, using a single conduit for directing a flowing stream of liquefied carbon dioxide into the containers. Y

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, taken with the accompanying drawing, in which:

Fig. 1 is a schematic view of apparatus illustrating the adaptation of the invention to the simultaneous filling of a plurality of permanently installed standard gas cylinders;

Fig. 2 is an enlargement of a portion of Fig. 1 showing in greater detail the arrangement of a manifold for carrying out the invention;

Fig, 2A is a view similar to the showing of Fig. 2 modified to illustrate an equal or larger number of cylinders and a manner in which such a group of cylinders may be lled.

Fig. 3 is a sectional view of one of the cylinders illustrating in detail the construction of the parts for conducting liquefied carbon dioxide into the cylinder and for limiting the amount thereof to a predetermined depth of liquid in the cylinder; and

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3.

As thus illustrated, the apparatus comprises a refrigerated tank II having insulated walls, shown partially in section at I2 and I3, suitable for confining a bulk supply of liquefied carbon dioxide at a moderately low pressure. It will be obvious that the liquefied gas in container I I will be at its boiling point and under a pressure corresponding to its vapor pressure at the temperature of the body of liquid. In other words, the liquid gaseous states are in equilibrium within the container. If desired, the tank II may be mounted on a truck indicated generally at I4, and may be provided with a low pressure centrifugal or gear pump I5 mounted on a suitable platform |16 at the rear of the truck. A pipe I1 extends from the interior IB of the tank I I below the level of liquid therein to the intake side of the pump I5. At the top of the tank II, there is provided an inspection port I9 closed by cover 20, through which a pipe 2| extends into the interior I8 of the tank II above the liquid level. The tank II may be filled with liquefied carbon dioxide either through pipe I1 or pipe 2|, and may be equipped with a safety valve (not shown) for the relief of gas pressure above a safe limit, for example, 325 pounds per square inch.

A fiexible conduit 22 such, for example, as a wire reinforced rubber hose, may be used to connect a nipple 23 provided at the discharge Side Qf 4 pump I 5 to a manifold assembly indicated generally at 24. A union 25 or other detachable fitting may effect the connection of conduit 22 to manifold 24. The manifold 24 may be constructed of any suitable arrangement of pipe or tubing with appropriate elbows and other fittings, including a plurality of Ts 26, and valves 21 and 28 pro- Vvided at its opposite ends, together with an outlet valve 23 and a pressure relief valve (not shown) located at suitable points in the manifold 24 between the valves 21 and 2B. A fiexible conduit 30, for example, a hose or the like, and similar to the conduit 22, may be used to connect elbow 3| on pipe 2| to a union or detachable fitting 32 on the manifold.

Each of the Tfs 26 is connected to a standard cylinder for containing carbon dioxide gas under pressure by means shown in the drawing as bushings 33, nipples 34, unions 35 and pipes 36. The pipes 36 extend downwardly into the cylinders to a point which corresponds to the desired predetermined level of liquefied carbon dioxide to be introduced therein. As shown in Fig. l, the cylinders 31 are mounted on a suitable platform or frame 38. As shown in detail at Fig. 3, the pipes 36 are threaded into the cylinders at 38 to form a gas-tight lconnection, in which case the pipes 36 are selected to correspond to the size of the neck opening of a standard cylinder.

In each of the pipes 36, there is provided a tube 40 which extends from the open extremity of pipe 36 within the cylinder to the upper interior of the manifold 24, for example, as shown within the T 26 of Fig. 3. The upper end of the tube 46 is preferably terminated at an angle of about 45 facing in the direction of the flow of liquid in the manifold. The tubes 40 may be secured in the interior of the pipes 36 in any suitable manner, for example, by welding or brazing as indicated at 4I and 42 of Fig, 3.

When the apparatus of our invention is used for filling gas cylinders or containers located remotely from a source of supply of carbon dioxide, the bulk supply tank II mounted on a mobile device or truck (as indicated in Fig. l) is used to transport a supply of liquefied carbon dioxide to the location of the containers to be filled. The manifold assembly may be, and preferably is, permanently mounted on the containers. When the tank II has been brought into the proper position, the hoses or flexible conduits 22 and 30 may be readily attached to the manifold 24 by means of fittings 25 and 32, and the valves 21 and 26 are opened so that any residual pressure of carbon dioxide gas in cylinders 31 is equalized with the pressure of the gaseous phase above the liquid in tank II. A power source (not shown) may then be started to operate pump I5 to draw liquefied carbon dioxide through the pipe I1 from the interior I8 of the delivery tank II. From the pump I5, the liquefied carbon dioxide will flow through the hose 22, valve 21, and into the manifold 24, from which the liquid moving in the direction indicated by arrows 43 will fiow through Ts 26 in succession, and by gravity into nipples 34, pipes 36 and into the corresponding cylinder 31, as indicated by arrow 44 in Fig. 3. Gas displaced in the cylinder by the liquid carbon dioxide will escape by means of tube 40 into the upper part of the manifold 24, and thence through the manifold in the direction indicated by arrows 45 from which it is returned to the gas space in tank I I by way of the conduit 30. It will be apparent that the gas pressure in the manifold 24 and cylinders 31 will therefore be equal to that above the liquid in tank Il at all times during the filling of the containers, and that no `greater pressure need be supplied by pump I than is necessary to move the liquefied carbon dioxide from the delivery tank i i to the manifold.

When the level of liqueed carbon dioxide in they first cylinder 3l reaches the extremities of pipe 36 and tube 4B, it will not be possible to dis-v place an additional quantity of gas from that cylinder, and no more liquid will enter it. Thus the amount of liquefied carbon dioxide in the cylinder Will be limited to a Ipredetermined level which, as stated above, may be calculated to correspond to the permissible filling density for the cylinder in question.v For purposes of illustration, the cylinder 31 in Fig. 3 is shown to be filled with liquid to the level of the ends of pipe 36 and tube 40;

When this condition is reached in the first cylinder, liquefied carbon dioxide will iiow from the manifold into the next cylinder which is provided with a pipe 36, and the process will be repeated until each of the cylinders thusly provided with a liquid lling pipe 35 in succession has received its predetermined quantity of liquefied carbon dioxide, and all of them have thus been sequentially filled to their respective predetermined levels. At this point, the pump may be stopped, -valves 21 and 28 closed, and conduits 22 and 30 detached from the manifold. If the pump is not stopped promptly upon the filling olf the last of cylinders 3l', no harm will result, since any additional liquefied carbon dioxide-will merely be circulated through the manifold and back to tank l I.

After the filling operation has been completed, the containers iand their contents will absorb heat from the atmosphere, and the liquid carbon dioxide will be thereby converted to the gaseous state, and hence available for use through valve 29 at the desired working pressure, which is usually initially around 1000 pounds per square inch.

In the construction and operation rof the system of this invention, certain details should be observed to insure its correct functioning. For example, each of the gas return tubes 40 should be secured in the filler pipes 3E so as to be located .at the downstream side of the connection between the manifold and the filler pipe leading into the cylinder as shown in Figs. 3 and 4. The reason Ifor the necessity of this par'ticular yar rangement is not clear, but it has been found by trial that the flow of liquefied gas downwardly from the manifold into the cylinders is severely retarded if the gas return tube lil is located at the upstream side of the connection between the manifold and branch pipe, and this effect has been noted to a lesser extent when the tube is located at one side of the opening. Also, in operatingthe filling method of this invention, the filling should be carried out continuously and at a fairly rapid rate once started, in order to minimize heat losses and to arrive at accurate filling densities by proper control of liquid levels in the cylinders, since it will be apparent that changes in the desired liquid levels could occur with material changes in the pressure on the system due to absorption of heat from the atmosphere during the operation. During'the filling operation, the rate at which liquefied gas is introduced into manifold 24 preferably should be approximately equal tothe rate at which the liquid fiows downwardly frointhe manifold into the cylinders through nipples34 and pipes36. The manifold 24 will thus be incompletely filled with the liquefied carbon dioxide during the iilling process, and a gas phase will exist in the manifold a't all times, and will thus facilitate the maintenance of equal pressures in all lparts of the system and the displacement of gas from the'cylinders through the tubesM) into the manifold and thence to the gas space above the liquid in tank Il. It is not essential tofrestrict the fiow of liquefied gas in the manifold to any particular rate, and the system will function as described even if liquid is pumped y,to the manifold `so rapidly that part of it is recirculate'd back to tank Il through conduit 30, although this is not a desirable condition.

It will be apparent that many modifications of the specific apparatus described are possible, and will occur to thoseskilled in `this art. Forexample, it is not necessary to employ the arrangement of Ts, bushings, nipples and unions, as shown in detail in the drawings, and the manifold and its branch connections to the cylinders may be otherwise formed, for example, of streamlined fittings or by welding or both.

In the case of a large number of' cylinders manifolded into a single permanently installed bank, it is not necessary that all of the cylinders be provided with the liquid :filling pipes 38 and gas return tubes 40, since provision may be made for initially introducing an yexcess of liquid into the cylinders that are provided with the liquid filling lines 3B and gas return tubes l0 to ll these to a slightly greater depth than is required for those particular cylinders. Thereupon, after the filling operation is completed, and when the liquefied gas is converted to the gaseous'state, the cylinders not so equipped will, by equalization of gas pressure in the system, receive the proper quantity of gas under the desired working pressure. It has been determined bytest that cylinders in the storage bank connected with the manifold but not provided with liquid filling pipes and gas return tubes will not receive' any significant amount of liquefied gas during the yfilling operation, and in large installations it may be found to be advantageous to provide only aportion, say, 60%, ofthe total number of cylinders in the bank with the liquid filling-lines and gas return tubes as shown at 36 and 40 in the drawings, and to charge the total quantity of gas in liquid form into these cylinders. f f

The use of our improved apparatus and the filling method described is extremely simple and rapid. It requires no gauges, scales, high pressure moving parts or special manipulation, and is virtually fool-proof in its functioning.

Example 1.-As onefexample ofthespeed and simplicity, ithas been found that with liquefied carbon dioxide in the tank Il under pressure -of approximately 290 pounds per square inchA and at a temperature of zero Fahrenheit, a bank of eight standard cylinders can be filled to contain fifty pounds each of carbon dioxide in approximatelytwo minutes. In this case, the manifold was made'up of standard'll/g" steelgpipe with corresponding fittings, as illustrated in the drawings. f' f y Example 2.-In another specific instance, li8 standard cylinders were manifolded together in accordance with the invention, using seamless steel tubing 1%" O. D. X 3% wall thickness with all Welded streamlined fittings in the construction of the manifold. `Thirty of the cylinders in this rbank were provided with liquid filling lines vand gas return tubes as shown at "36 and 40 of the drawings, and the remaining IB cylinders were connected to the manifold by open pipes terminated in their neck openings. With the bulk supply of liquid carbon dioxide again under a pressure of about 290 pounds per square inch at about zero Fahrenheit, and with an atmospheric temperature of 70 F., the entire bank was fully charged with the required amount of carbon dioxide in minutes, all of the gas being received in liquid form by the 30 cylinders provided with liquid filling lines and gas return tubes.

In neither of the two instances just described, did there occur any significant increase in gas pressure in the system due to absorption of heat during the filling operation, and the rapidity with which this operation can be conducted precludes this in all cases. The rather extreme cold produced in the cylinders during their filling with liquefied carbon dioxide incidentally provides a convenient and simple means of informing the operator when the last cylinder to be filled has received its charge of liquefied gas, since each cylinder in turn as it is filled displays a frost coating of moisture condensed and frozen out of the surrounding atmosphere, and the extent of this plainly visible white coating of frost on the cylinders accurately follows the level of liquid within the cylinders.

The system and apparatus described herein is far more flexible than low pressure bulk storage systems heretofore employed. For example, the initial cost of installing a system as described above is only about one-half the cost of installing a low pressure storage system of the same capacity. In addition, the present system allows the storage containers or cylinders to be manifolded to occupy a minimum of space which may follow almost any available form, whereas the installation of a low pressure storage tank requires a greaterarea that is fixed as to both its extent and shape. The present system relies exclusively upon atmospheric heat to vaporize the liquid and raise the gas in the containers to the desired working pressure as well as to offset the cooling effect encountered upon withdrawal of gas for use. Low pressure storage tanks necessarily must be insulated to prevent absorption of atmospheric heat that would otherwise cause excessive pressure increase, and thus they require heat to ofi'set the cooling effect produced when the gas is withdrawn for use. Finally, the low pressure storage system requires a continuous source of power for its refrigeration and heating cycles, whereas the system of this invention requires only a modest power source to operate the pump which is used but for a short time to introduce liquefied gas into the manifold when the system is being replenished, and since the pump properly should be considered part of the bulk delivery system to service many storage installations, the power requirement of the storage bank is nil. Thus, the cost of operating our system is negligible as compared to that of the low pressure system.

It will be apparent that the apparatus and method disclosed above completely obviates the necessity for either weighing of the gas at any point in its handling, or measuring the level of a liquid in a closed container. In the low pressure system, the delivery bulk supply tank must be weighed to determine the amount of gas transferred to the storage system, or alternatively, the quantity of gas must be measured by a liquid level indicator, which in the case of the liquefied gas at its boiling point as it exists in the system is inherently an unreliable measurement.

It will be understood that the apparatus and method of our invention may be used to fill any number of cylinders or like containers sequentially and more or less simultaneously to any desired level of liquefied gas therein, and that the bulk supply tank need not be mobile if the system is employed to fill portable containers.

The invention has been described with'particular reference to carbon dioxide, and it has special value when applied to the handling of this gas. It may, of course, be equally well applied to other gaseous substances which exist in liquid state at readily attainable pressures and temperatures, and which are capable of being converted from liquid to the gaseous state by atmospheric heat or by other readily available heat. In any case, the system of this invention is applicable only to liquefied gases at their boiling points and at the vapor pressure of the liquid involved.

This application is a continuation-in-part of our copending application Serial No. 753,198, filed June 7, 1947, now abandoned.

We claim:

1. Method of filling a closed container to a predetermined level with a liquefied gas from a bulk supply thereof in equilibrium with its gaseous phase, which method includes establishing a single confined stream of said gas flowing from the liquid of said bulk supply above said container and comprising both a liquefied gas and a gaseous phase, connecting the interior of said closed container at said predetermined level with the liquid of said stream and separately with the geasous phase of said stream, connecting said stream beyond said container with the gaseous phase above the liquid of said bulk supply, and maintaining a flow of liquefied gas in said stream for a period at least sufficient to fill said container with liquid to said predetermined level.

2. Method of sequentially filling a plurality of closed containers to a predetermined level in each of a liquefied gas from a bulk supply thereof in equilibrium with its gaseous phase, which method includes establishing a single confined stream of said gas flowing from the liquid of said bulk supply above said containers and cornprising both liquefied gas and a gaseous phase, connecting the interior of each of said closed containers at its predetermined level with the liquid of said stream and separately with the gaseous phase of said stream, connecting said stream beyond all of said containers with the gaseous phase above the liquid of said bulk supply, and maintaining a flow of liquefied gas in said stream for a period at least sufficient to fill each of said containers with liquid to its said predetermined level.

3. Method of filling a. closed container to a predetermined level with liquefied carbon dioxide from a bulk supply thereof in equilibrium with its gaseous phase, which method includes establishing a single confined stream of carbon dioxide flowing from the liquid of said bulk supply above said container and comprising both a liquid and a gaseous phase, connecting the interior of said closed container at said predetermined level with the liquid of said stream and separately with the gaseous phase of said stream, connecting said stream beyond said container with the gaseous phase above the liquid of said bulk supply, and maintaining a flow of liquefied 4. Method of sequentially filling a plurality of closed-.containers to a predetermined` level in each of liquefied carbon dioxide from a bulk supply 'thereof in equilibrium with its gaseous phase, which method includes establishing a single confined stream or" vcarbon dioxide iiowing from the liquid of said bulli: supply above said containers and comprising both a liquid and a gaseous phase, connecting the interiorof each of said closed containers at its predetermined level with the liquid of said stream and separately with the gaseous phase of said stream, connecting said stream beyond all of said containers with the gaseous phase above the liquid of said bulk supply, and maintaining a flow of liquefied carbon dioxide in said stream for a period at least sumcient to'fill each'of said containers with liquid to its said predetermined level. v

y5. Method of sequentially filling a plurality of closed containers to a predetermined level in each of liquefied carbon dioxide from a bulk supply thereof in equilibrium with its gaseous phase, which method includes establishing a single confined stream of carbon dioxide nowing from the liquid of said bulk supply above said containers and comprising both a liquid Vand a gaseous phase, connecting the interior of each of said closed containers at its predetermined level with the liquid of said stream and separately withV stream beyond all of said containers with the gaseous phase above the liquid of said bulksupply, and maintaining a flow of liquefied carbon dioxide in said stream approximately equal to the rate of iiow of liquid into said containers for a period at least sufficient to fill each of said containers with liquid to its said predetermined level.

6. Method of filling a cylinder with a predetermined quantity of gas under pressure from a bulk supply of said gas in liquid form and in equilibrium with its gaseous phase, which method includes establishing a single confined stream of said gas flowing from the liquid of said bulk supply above said cylinder and comprisingboth liquefied gas and a gaseous phase, connecting the interior of said cylinder at a point corresponding to a level of liquefied gas therein equal to said predetermined quantity of gas with the liquid of said stream and separately connecting the same point with the gaseous phase of said stream, connecting said stream beyond said cylinder with the gaseous phase above the liquid of said bulk supply, maintaining a flow of liquefied gasin said stream for a period at least sufficient tofill said cylinder to said level, and thereafter vaporizing the liquefied gas in said cylinder.

'7. Method of filling a plurality of cylinders with a predetermined quantityof gas under pressure from a bulk supply of said gas in liquid form and in equilibrium with its gaseous phase, which method includes establishing a singleconfined stream of said gas flowing from the liquid of said bulk supply above said cylinders and comprising both liquefied gas and a gaseous phase, connecting the top openings only of a first group of said cylinders with said confined stream, connecting the interior of each of a second group constituting the balance of said cylinders at a point corresponding to a level of liquefied gas therein which provides a total quantity of liquefied gas in all of the cylinders of said second group which 10 will produce the said predetermined quantity of gasvv in the cylinders of bothv groups, separately connecting the same point in the interiors of each of said second group -of cylinders with the gaseous phase ofy said stream, connecting said stream beyond all of said cylinders with the gaseous phase above the liquid of said bulk supply, maintaining allow of liquefied gas in said stream after said connections have been made for a period at least sufiicient to fill each of said second group of cylinders to said level, and thereafter vaporizing thev liquefied gas in the second group of cylinders to fill all of said cylinders with said ypredetermined quantity of gas.

8. Method of filling a plurality of cylinders with a predetermined quantity of carbon dioxide under pressure fromV a bulk supply of carbon dioxide in liquid form and in equilibrium with its gaseous phase, which method includes establishing a single confined stream of carbon dioxide flowing from the liquid of said bulk supply above said cylinders and comprising both liquefied carbon dioxide and a gaseous phase, rconnecting the top openings only of av first group of said cylinders with said confined stream, connecting the interior of each of a second group constituting the balance of said cylinders at a point corresponding to a level of liquefied carbon dioxide therein which provides a total quantity of liquefied gas in all of the cylinders of said second group which will produce the said predetermined quantity of gaseous carbon dioxide in the cylinders of both groups, separately connecting the same point in the interiors of each of said second group of cylinders with the gaseous phase of said stream, connecting said stream beyond all of said cylinders with the gaseous phase above the liquid of said bulk supply, maintaining a flow of liquefied carbon dioxide in said stream after said connections have been made for a period at least Asufficient to fill each of said second group of cylinders to said level, and thereafter vaporizing the 'liquefied carbon dioxide in the second group of cylinders to fill all of said cylinders with said pre- 'determined quantity of carbon dioxide.

9. In an apparatus for filling a container toa predetermined level with liquefied gas from a bulk Asupply thereof in equilibrium with its gaseous phase: the combination of a manifold disposed above said container and having a single passage therein, means to supply liquefied gas from said bulk supply to the inlet of said manifold, and means connecting the outlet of said manifold with the space above the liquid of said bulk supply; a conduit through which liquefied gas may flow extending from a lower portion of said manifold into the interior of saidcontainer, and terminating at said predetermined level; and a second conduit disposed within said first-mentioned conduit connecting said level with an upper portion of the interior of said manifold to provide a passagethrough which gas may pass frOmsaid f container into said lmanifold and thence to the space above the liquid of said bulk supply.

10. In an `apparatus for filling a plurality of containers to a predetermined level with liquefied gas from a bulk supply thereof which is in equilibrium with the gaseous phase thereof: the combination of a manifold having a single passage therein and having its inlet connected to said bulk supply of liquefied gas and its outlet connected to the space above the liquid in said bulk supply; pipes in communication with said manifold and said containers through Which said liquefied gas may `flow from the former into the latter, said pipes extending downwardly into said containers to said predetermined level; and tubes disposed within said pipes extending from said predetermined level within said containers into an upper portion of the interior of said manifold, said tubes providing passages through which gas may pass from said containers into said manifold and thence to the space above the liquid in said bulk supply.

11. In an apparatus for filling a plurality of containers to a predetermined level with liquefled gas from a bulk supply thereof in equilibrium with its gaseous phase: the combination of a manifold disposed above said containers and having a single passage therein, means to supply liquefied gas from said bulk supply to the inlet f said manifold, and means connecting the outlet of said manifold .with the space above the liquid of said bulk supply; conduits through which liquefied gas may flow from a lower portion of said manifold into the interior of each of said containers and terminating at said predetermined level; and a separate conduit disposed within each of said first-mentioned conduits connecting said level with an upper portion of the interior of said manifold to provide passages through which gas may pass from said containers into said maninfold and thence to the space above the liquid of said bulk supply.

12. In an apparatus for filling a plurality of containers to a predetermined level with liquefied carbon dioxide from a bulk supply thereof in equilibrium with its gaseous phase: the combination of a manifold disposed above said containers and having a single passage therein, means to supply liquefied carbon dioxide from said bulk supply to the inlet of said manifold, and means connecting the outlet of said manifold with the space above the liquid of said bulk supply; conduits through which liquefied carbon dioxide may flow extending from a lower portion of said manifold into the interior of each of said containers and terminating at said predetermined level; and a separate conduit disposed within each of said first-mentioned conduits connecting said level with an upper portion of the interior of said manifold to provide passages through which carbon dioxide may pass from said containers into said manifold and thence to the space above the liquid of said bulk supply.

13. In an apparatus for filling a plurality of cylinders with a predetermined quantity of gas under pressure from a bulk supply of said gas in liquefied form in equilibrium with its gaseous phase: the combination of a manifold disposed above said cylinders and having a single passage therein, means to supply liquefied gas from said bulk supply to the inlet of said manifold, and means connecting the outlet of said manifold with the space above the liquid of said bulk supply; conduits connecting the top openings only of a first group of said cylinders with said manifold; conduits through which liquefied gas may flow extending from a lower portion of said manifold into the interior of each of a second group of said cylinders and terminating at a point in each corresponding to a level of liquefied gas therein which provides a total quantity of liquefied gas in all of the cylinders of said second group which will produce the said predetermined quantity of gas in the cylinders of both groups; a second conduit disposed within each of the said first-mentioned conduits in the cylinders of said second group connecting said level with an upper portion of the interior of said manifold to provide passages through which gas may pass from the interior of the cylinders of said second group into said manifold and thence to the space above the liquid of said bulk supply; and means to disconnect the inlet and outlet of said manifold from said bulk source of supply whereby all of said cylinders will be in communication with each other through said manifold for the equalization of gas pressure resulting from Vaporization of said liquefied gas.

14. In an apparatus for filling a container to a predetermined level with liquefied gas from a bulk supply thereof in equilibrium with its gaseous phase: the combination of a manifold disposed above said container and having a single passage therein, means to supply liquefied gas from said bulk supply to the inlet of said manifold, and means connecting the outlet of said manifold with the space above the liquid of said bull: supply; a conduit through which liquefied gas may flow from a lower portion of said manifold into the interior of said container and terminating at said predetermined level; and a second conduit disposed within said first-mentioned conduit connecting said level with an upper portion of the interior of said manifold in which it terminates in an oblique opening facing downstream of the flow of liquefied gas in said manifold to provide a passage through which gas may pass from said container into said manifold and thence to the space above the liquid of said bulk supply.

PAUL F. DROSTE. CHARLOTTE R. HILL,

Administratria: of the estate of Howard J. Hill,

deceased.

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